Catalyzed HF Vapor Etching of Silicon Dioxide for Micro- and NanolithographicMasks

摘要

A novel means of pattern generation and transfer combining electron beamlithography of scanning tunneling microscopy (STM) patterning with HF vapor etching is reported. HF vapor etch rates in silicon dioxide are found to be markedly enhanced by the presence of adsorbed hydrocarbon species that have been positionally fixed in either the electron beam tool or using the STM. Etch selectivities of at least 100 have been shown to be achievable in electron beam experiments for pattern generation. The relationships that exist between electron beam parameters and the observed etch rates are discussed in terms of possible chemical mechanism extent on the surface during and after electron beam exposure. Feature generation in silicon dioxide using electron beam approaches is reported for <100 nm linewidths. Utilizing STM as the lithographic tool, the formation of oxide trenches as narrow as 3 to 5 nm has been shown to be feasible. The STM generated oxide patterns were successfully transferred to silicon using reactive ion etching techniques.